1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165


use std::marker::PhantomData;
use siege_math::{Vec3, Mat3};

#[derive(Debug, Clone, Copy)]
pub struct D50;
#[derive(Debug, Clone, Copy)]
pub struct D60;
#[derive(Debug, Clone, Copy)]
pub struct D65;
pub trait Illuminant { }
impl Illuminant for D50 { }
impl Illuminant for D60 { }
impl Illuminant for D65 { }


/// CIE 1931 XYZ colorspace at the D65 whitepoint
/// Normalized to Y=1.0 (Not Y=100 !!!)
#[derive(Debug, Clone)]
pub struct Cie1931<I: Illuminant> {
    pub v: Vec3<f32>,
    _phantom: PhantomData<I>
}

impl<I: Illuminant> Cie1931<I> {
    pub fn new(x: f32, y: f32, z: f32) -> Cie1931<I> {
        Cie1931 {
            v: Vec3::new(x, y, z),
            _phantom: Default::default()
        }
    }

    #[inline]
    pub fn x(&self) -> f32 {
        self.v.x
    }
    #[inline]
    pub fn y(&self) -> f32 {
        self.v.y
    }
    #[inline]
    pub fn z(&self) -> f32 {
        self.v.z
    }

    pub fn get_luminance(&self) -> f32 {
        self.v.y
    }

    pub fn set_luminance(&mut self, luminance: f32) {
        let scale = luminance / self.v.y;
        self.v *= scale;
    }
}

impl From<Cie1931<D65>> for Cie1931<D50> {
    fn from(input: Cie1931<D65>) -> Cie1931<D50>
    {
        let m: Mat3<f32> = Mat3::new(
            1.047844353856414, 0.022898981050086, -0.050206647741605,
            0.029549007606644, 0.990508028941971, -0.017074711360960,
            -0.009250984365223, 0.015072338237051, 0.751717835079977
        );

        Cie1931 {
            v: &m * &input.v,
            _phantom: Default::default()
        }
    }
}

impl From<Cie1931<D50>> for Cie1931<D65> {
    fn from(input: Cie1931<D50>) -> Cie1931<D65>
    {
        let m: Mat3<f32> = Mat3::new(
            0.9555491471339036, -0.02305395902610921, 0.0632967285241842,
            -0.028293615880275732, 1.009916725621172, 0.021049798533869513,
            0.012326727844429515, -0.020533074478247797, 1.3306432822046876
        );

        Cie1931 {
            v: &m * &input.v,
            _phantom: Default::default()
        }
    }
}


// CIE 1931xy colorspace
// FIXME - is this type parameterized by an illuminant?
#[derive(Debug, Clone)]
pub struct Cie1931xyY {
    pub v: Vec3<f32>
}

impl Cie1931xyY {
    #[allow(non_snake_case)]
    pub fn new(x: f32, y: f32, Y: f32) -> Cie1931xyY {
        Cie1931xyY {
            v: Vec3::new(x, y, Y)
        }
    }

    pub fn x(&self) -> f32 {
        self.v[0]
    }
    pub fn y(&self) -> f32 {
        self.v[1]
    }
    pub fn z(&self) -> f32 {
        self.v[2]
    }
}

impl From<Cie1931<D65>> for Cie1931xyY {
    fn from(input: Cie1931<D65>) -> Cie1931xyY {
        let mut divisor: f32 = input.v[0] + input.v[1] + input.v[2];
        if divisor==0.0 { divisor = 1e-10; }
        Cie1931xyY::new(
            input.v[0] / divisor,
            input.v[1] / divisor,
            input.v[1]
        )
    }
}

impl From<Cie1931xyY> for Cie1931<D65> {
    fn from(input: Cie1931xyY) -> Cie1931<D65> {
        Cie1931::new(
            input.v[0] * input.v[2] / input.v[1].max(1e-10),
            input.v[2],
            (1.0 - input.v[0] - input.v[1]) * input.v[2] / input.v[1].max(1e-10)
        )
    }
}


#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn cie1931_to_from() {
        let a = Cie1931::<D65>::new(0.123, 1.0, 0.234);
        let b: Cie1931xyY = From::from(a.clone());
        let c: Cie1931<D65> = From::from(b);

        assert!(a.v[0] - c.v[0] < 0.000001);
        assert!(c.v[0] - a.v[0] < 0.000001);
        assert!(a.v[1] - c.v[1] < 0.000001);
        assert!(c.v[1] - a.v[1] < 0.000001);
        assert!(a.v[2] - c.v[2] < 0.000001);
        assert!(c.v[2] - a.v[2] < 0.000001);
    }

    #[test]
    fn invert_test() {
        let c1 = Cie1931::<D50>::new(0.998123, 0.24987234, 0.45287234);
        let c2: Cie1931<D65> = From::from(c1.clone());
        let c3: Cie1931<D50> = From::from(c2);

        use float_cmp::ApproxEq;
        assert!( c1.v.approx_eq(&c3.v, 10, 10.0 * ::std::f32::EPSILON) );
    }
}